Cuvette assembly having chambers for containing samples to be evaluated through optical measurement

ABSTRACT

The present invention is a cuvette assembly for use in optically measuring at least one characteristic of particles within a plurality of liquid samples. The cuvette assembly comprises a main body having internal walls and external walls, and a plurality of cuvettes within the main body at least partially being defined by the internal walls. Each of the plurality of cuvettes has a liquid-input chamber for receiving a respective one of the plurality of liquid samples, a filter, and an optical chamber for receiving a respective filtered liquid sample caused by passing the respective one of the plurality of liquid samples through the filter. Each of the optical chambers includes an entry window for allowing transmission of an input light beam through the filtered liquid sample and an exit window for transmitting a forward scatter signal caused by the particles within the filtered liquid sample.

RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/562,304, filed Dec. 5, 2014, and titled “Cuvette Assembly HavingChambers For Containing Samples To Be Evaluated Through OpticalMeasurement,” now allowed, which claims priority to U.S. ProvisionalApplication Ser. No. 61/912,763, filed Dec. 6, 2013, and titled“Multi-Cuvette,” each of which is herein incorporated by reference inentirety.

COPYRIGHT

A portion of the disclosure of this patent document may contain materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patentdisclosure, as it appears in the Patent and Trademark Office patentfiles or records, but otherwise reserves all copyright rightswhatsoever.

FIELD OF THE INVENTION

The present invention relates generally to the field of opticalmeasurements of contained liquid samples. Specifically, the presentinvention relates to a cuvette assembly having multiple chambers forcontaining samples, such as liquid samples, that will be evaluated byoptical measurements through windows associated with the chambers.

BACKGROUND OF THE INVENTION

Many applications in the field of analytical research and clinicaltesting utilize optical methods for analyzing liquid samples. Amongthose methods are absorbance, turbidity, fluorescence/luminescence, andoptical scattering measurements. Optical laser scattering is one of themost sensitive methods, but its implementation can be very challenging,especially when analyzing biological samples in which suspendedparticles are relatively transparent in the medium. In this case, mostof the scattering process occurs in the forward direction near theincident laser beam. To detect this forward scattering signal, highextinction of the incident beam is required.

One particle that often requires evaluation within a liquid is bacteria.The presence of bacteria is often checked with biological liquids, suchas urine, amniotic, pleural, peritoneal and spinal liquids. In a commonanalytical method, culturing of the bacteria can be time-consuming andinvolve the use of bacterial-growth plates placed within incubators.Normally, laboratory results take several days to determine whether thesubject liquid is infected with bacteria.

In some systems, cuvettes have been used to receive liquid samples thatare then subjected to the optical measurement by transmission of aninput beam through the cuvette and observation of the forward scattersignals. These devices have been used relative to the detection ofbacteria within the liquid. However, the cuvettes are not conducive tomass production for commercial use. Nor do these prior art cuvettes haveuser friendly features that permit for ease of use by operators.Furthermore, these prior art cuvettes lack mechanisms that permit theeasy flow of the liquid sample into the optical chamber through afilter.

Accordingly, there is a need for an improved cuvette that is easy tomass produce, permits easy use by the operator, and more readilydelivers the liquid sample into the optical chamber through the filter.

SUMMARY OF THE INVENTION

The present invention is a cuvette assembly for use in opticallymeasuring at least one characteristic of particles within a plurality ofliquid samples. The cuvette assembly comprises a main body havinginternal walls and external walls, and a plurality of cuvettes withinthe main body are at least partially defined by the internal walls. Eachof the plurality of cuvettes has a liquid-input chamber for receiving arespective one of the plurality of liquid samples, a filter, and anoptical chamber for receiving a respective filtered liquid sample causedby passing the respective one of the plurality of liquid samples throughthe filter. Each of the optical chambers includes an entry window forallowing transmission of an input light beam through the filtered liquidsample and an exit window for transmitting a forward scatter signalcaused by the particles within the filtered liquid sample.

In another aspect, the present invention involves a cuvette assembly foruse in optically measuring at least one characteristic of particleswithin a plurality of liquid samples. The cuvette assembly includes amain body having a plurality of openings. Each opening is for receivinga respective one of the plurality of liquid samples. Each of theplurality of openings leads to an associated liquid-input chamber thatis in fluidic communication with an associated optical chamber. Eachoptical chamber has an entry window for allowing transmission of aninput light beam through the respective liquid sample and an exit windowfor transmitting a forward scatter signal caused by the particles withinthe respective liquid sample. The cuvette assembly further includes aplurality of individual closure mechanisms. Each of the plurality ofclosure mechanisms is associated with a respective one of the pluralityof openings. Each of the plurality of closure mechanisms is movable froman initial opened position for receiving the respective liquid sample toa closed position that inhibits leakage from the associated liquid-inputchamber.

In a further aspect, the present invention is a cuvette assembly for usein optically measuring at least one characteristic of particles within aplurality of liquid samples. The cuvette assembly includes a main bodyhaving internal walls that at least partially define a plurality ofoptical chambers for receiving a respective one of the plurality ofliquid samples. Each of the optical chambers includes an entry windowfor allowing transmission of an input light beam through the respectiveliquid sample and an exit window for transmitting an optical signalcaused by the particles within the respective liquid sample. The mainbody further including a lower surface that is at an angle relative to acentral axis of the input light beam. A first pair of registrationstructures is associated with the angled lower surface of the main body.The first pair of registration structures is intended to mate with acorresponding pair of registration features on a platform in aninstrument associated with a light source producing the input lightbeam.

In yet a further aspect, the present invention is a cuvette assembly foruse in optically measuring at least one characteristic of particleswithin a plurality of liquid samples. The cuvette assembly comprises aplurality of cuvettes. Each of the plurality of cuvettes has aliquid-input chamber for receiving a respective one of the plurality ofliquid samples, a filter, and an optical chamber for receiving arespective filtered liquid sample from the filter. Each optical chamberincludes a vent for allowing displaced gas to escape as the filteredliquid sample enters the optical chamber.

In yet another aspect, the present invention is a cuvette assembly foruse in optically measuring at least one characteristic of particleswithin a plurality of liquid samples. The cuvette assembly comprises aplurality of cuvettes. Each of the plurality of cuvettes has aliquid-input chamber for receiving a respective one of the plurality ofliquid samples, a filter, and an optical chamber for receiving arespective filtered liquid sample from the filter. The cuvette assemblyincludes ports to receive applied pressure to the liquid samples withinthe liquid-input chamber so as to force the samples through the filtersand into the optical chambers. Or, the cuvette assembly includes port(s)associated with the optical chamber to apply a suction force (or avacuum) to draw the filtered liquid sample through the filter and intothe optical chamber.

In another aspect, the present invention is a cuvette assembly for usein optically measuring at least one characteristic of particles within aplurality of liquid samples. The cuvette assembly comprises a pluralityof cuvettes within a main body of the cuvette assembly. Each of theplurality of cuvettes has a liquid-input chamber for receiving arespective one of the plurality of liquid samples and an optical chamberfor receiving a respective liquid sample from the associatedliquid-input chamber. Each of the optical chambers includes an entrywindow for allowing transmission of an input light beam through theliquid sample and an exit window for transmitting an optical signalcaused by the particles within the liquid sample. At least one windowassembly is attached to the main body that includes either (i) all ofthe entry windows for the plurality of optical chambers or (ii) all ofthe exit windows for the plurality of optical chambers.

In another aspect, the present invention is a cuvette assembly for usein optically measuring at least one characteristic of particles within aplurality of liquid samples. The cuvette assembly comprises a pluralityof cuvettes. Each of the plurality of cuvettes has a liquid-inputchamber for receiving a respective one of the plurality of liquidsamples and an optical chamber for receiving a respective liquid samplefrom the associated liquid-input chamber. Each of the optical chambersincludes an entry window for allowing transmission of an input lightbeam through the liquid sample and an exit window for transmitting anoptical signal caused by the particles within the liquid sample. Eachcuvette is preloaded with one or more chemo-effectors for mixing withliquid sample located therein.

Additional aspects of the invention will be apparent to those ofordinary skill in the art in view of the detailed description of variousembodiments, which is made with reference to the drawings, a briefdescription of which is provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a sectional view through theliquid-input chamber and optical chamber of one cuvette of a cuvetteassembly in accordance with the present invention.

FIG. 2 is a top plan view of the cuvette assembly of FIG. 1.

FIG. 3 is an exploded view of another embodiment of a cuvette assemblyhaving multiple chambers in accordance with the present invention.

FIG. 4 is a perspective view of a cuvette assembly of FIG. 3 with thefirst optical chamber and associated liquid-input chamber illustrated ina sectional view.

FIG. 5 is a cross-sectional view through the exit window assembly takenalong line 5-5 of FIG. 7.

FIG. 6 is a schematic view of one optical chamber of the cuvetteassembly of FIG. 3 in response to an input beam being transmittedthrough the entry window.

FIG. 7 is an exploded view of the cuvette assembly of FIG. 4 showing thevarious alignment and registration features at the bottom of the cuvetteassembly.

FIG. 8 illustrates the cuvette assembly of FIG. 4 registered on aplatform that is typically located within an optical measurementinstrument.

FIG. 9 illustrates a cuvette assembly having a contamination-preventionfilm located over the upper structure of the cuvette assembly.

FIG. 10 illustrates yet another embodiment of the cuvette assemblyaccording to the present invention that includes a frangible filmdirectly below the openings of the cuvette assembly.

FIG. 11 illustrates yet a further embodiment of the cuvette assemblyaccording to the present invention that includes a manual pump to helpforce a liquid within the upper liquid-input chamber through a filter sothat it enters the lower optical chamber.

FIG. 12 schematically illustrates one application for the cuvetteassemblies according to the present invention in which a single cuvetteassembly contains a control sample and four different drug samples, or acontrol sample and four different dosages of a single drug sample.

While the invention is susceptible to various modifications andalternative forms, specific embodiments will be shown by way of examplein the drawings and will be described in detail herein. It should beunderstood, however, that the invention is not intended to be limited tothe particular forms disclosed. Rather, the invention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

The drawings will herein be described in detail with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit the broadaspect of the invention to the embodiments illustrated. For purposes ofthe present detailed description, the singular includes the plural andvice versa (unless specifically disclaimed); the words “and” and “or”shall be both conjunctive and disjunctive; the word “all” means “any andall”; the word “any” means “any and all”; and the word “including” means“including without limitation.”

FIGS. 1 and 2 schematically illustrate a first embodiment of the cuvetteassembly 10 according to the present invention. As shown in FIG. 2, thecuvette assembly 10 includes five optical chambers 12 a, 12 b, 12 c, 12d, 12 e defined by internal and external walls on a lower portion 13 ofthe main body of the cuvette assembly 10. As illustrated in FIG. 1, aliquid-input chamber 14 is located above each optical chamber 12 and isalso defined by internal and external walls on the upper portion 15 ofthe main body of the cuvette assembly 10. Each liquid-input chamber 14and its associated optical chamber 12 form an individual cuvette. Thecuvette assembly 10 is preferably made of plastic material, such aspolycarbonate, polystyrene, or ABS, and is preferably disposable.

The optical chamber 12 of the cuvette assembly 10 includes an entrywindow 16 and an exit window 18. A light source 20, such as a laser,provides an input beam (solid line) that passes from the entry window16, through a liquid sample within the optical chamber 12, and throughthe exit window 18. When the liquid sample includes particles, a forwardscattering signal (dashed lines) is produced by the impingement of theinput beam on the particles within the liquid sample and is detected bya sensor 22. The forward scattering signal provides characteristics(e.g., quantity, size, or concentration) of the particles present in theliquid sample, which is useful for diagnostic applications, medicalapplications, non-medical applications, and research applications. Inone particularly useful application, the particles are bacteria, whichcan be detected and counted by various techniques that are generallydescribed in U.S. Pat. Nos. 7,961,311 and 8,339,601, both of which arecommonly owned and are herein incorporated by reference in theirentireties.

As seen in FIGS. 1-2, the optical chamber 12 within the lower portion 13of the main body has angled walls in the horizontal and vertical planes.The angled walls provide an optical chamber that is roughly conic with asmaller entry window 16 than the exit window 18 so that light can spreadfrom the entry window 16 without impinging on the walls. In oneembodiment, the opposing angled walls are within 12° to 16° of parallelto the input beam (i.e., each vertical wall and horizontal wall iswithin about 6° to 8° of a central axis of the optical chamber 12).Also, angled “light traps” might be incorporated into the angled wallsof the optical chamber 12 to trap, absorb, and/or contain interior lightreflections from the windows 16, 18 or wall surfaces.

The windows 16, 18 at each end of the optical chamber 12 are transparentto the input beam. The windows 16, 18 are thin (less than 1 mm) and aretipped at an angle to ensure that the surfaces of the windows 16, 18 arenot normal to the input beam so as to reduce retro-reflections thatmight interfere with the measurement of the forward scattering signal atthe sensor 22. The windows 16, 18 can be angled in the same or differentplanes. The windows 16, 18 can be glass or plastic, and can also be aplastic film. They must have low surface roughness (preferably a surfacemicroroughness less than 100 angstroms rms) and minimum inclusions thatwould produce scatter, which could also interfere with the measurementof the forward scattering signal at the sensor 22.

Regarding the transfer of the liquid sample from the upper portion 15 tothe lower portion 13 of the cuvette assembly 10, the liquid sample isinitially located within the liquid-input chamber 14 and is then passedthrough a filter 32 (e.g., a permeable membrane 32) into the opticalchamber 12. The filter 32 removes particles of a particular size, forexample excluding particles larger than bacteria by filtering to belowabout 0.01 mm (about 10 microns), leaving only certain sized particlespresent in the filtered liquid sample located in the optical chamber 12.An intermediate partition 30 within the cuvette assembly 10 supports thefilter 32 and includes a group of openings that permit the filteredliquid sample to pass from the liquid-input chamber 14 into the opticalchamber 12. Alternatively, the intermediate partition 30 may haveopenings that are sized and shaped to provide enough filtering so as toavoid the need for the additional filter 32.

The cuvette assembly 10 may also include a foil or frangible membrane 34(or one-use frangible feature) below an opening 40 on the upperstructure 38 of the main body to seal the interior of the liquid-inputchamber 14 before use of the cuvette assembly 10. The foil or frangiblemembrane 34 could be pierced or displaced by a standard pipette, syringetip, sharp cannula, or other tube that injects the liquid sample intothe liquid-input chamber 14. This foil or frangible membrane 34 servesto protect the integrity or sterility of the interior of theliquid-input chamber 14 and the optical chamber 12 prior to use, andalso provides tamper-evidence or use-evidence for a user. The frangiblemembrane 32 could also be a resilient or rubber material so that itcould be pierced by a sharp cannula, but still retain the liquid sampleinside the liquid-input chamber 14 and below the frangible membrane 32after being pierced. Several mechanisms exist for blunt cannula access(such as those mechanisms used in needleless infusion devices) might beincorporated to allow transfer of the liquid sample into the interior ofthe liquid-input chamber 14. For example, these mechanisms may include aslideable or deformable rubber element mounted in a tubular body, with aslit or opening in the element that is forced open by being displaced bya syringe luer taper. They may also include a spring-loaded valve poppetor moveable element that can be displaced from a sealing ring by beingdisplaced by a blunt cannula, or a “duck-bill” collapsed rubber tubethat can be forced open by a blunt cannula.

The intermediate partition 30 may also help to form a vent (not shown inFIGS. 1-2) from the optical chamber 12 to the upper region of theliquid-input chamber 14 to facilitate venting air (or other gas) that isdisplaced from the optical chamber 12 upon receipt of the filteredliquid sample. There may also be a feature to connect this vent througha wall of the liquid-input chamber 14 to an apparatus outside thecuvette assembly 10 for applying a vacuum to the optical chamber 12 topromote liquid moving through the filter membrane 32 and/or intermediatepartition 30, which is shown in more detail in FIG. 9. This vent may besmall (e.g., less than 3 mm diameter, or less than 1 mm) or include arestrictive section or aperture so that fluid pulled by vacuum throughthe vent encounters substantial flow resistance (back pressure), whichcan be detected by the vacuum apparatus to indicate that the opticalchamber 12 is filled and to cease applying the vacuum. Once the filteredliquid sample is within the optical chamber 12, the optical measurementsassociated with the light source 20 and the sensor 22 may be initiated.

To maintain liquid samples within the cuvette assembly 10 after theyhave been introduced into the liquid-input chambers 14 via the openings40, a closure mechanism 42 is associated with each of the liquid-inputchambers 14 of the cuvette assembly 10. The closure mechanism 42 ispreferably a single-use sliding closure that preferably provides alocking feature after it is moved from an initial opened position (solidlines) to a closed position (dashed lines). The sliding closuremechanism 42 could have a ratchet or pall device incorporated therein tolock it in the closed position on the upper structure 38 so that thecuvette assembly 10 is assured of only a single use. The sliding closuremechanism 42 also served as evidence of use. The sliding closuremechanism 42 preferably includes a wiping feature to ensure aliquid-tight closure that inhibits or precludes leakage of liquid fromthe liquid-input chamber 14. The sliding closure mechanism 42 andassociated wiping feature also ensure that exterior contaminants cannotbe introduced into the liquid-input chamber 14 after the sliding closuremechanism 42 is in the closed position. Furthermore, the sliding closuremechanism 42 preferably has a configuration that is tailored to fit apipette or loading tube to preclude liquid or gas leaking around thetube, or to wipe the end of the tube as it is withdrawn from the opening40. Alternatively, the closure mechanism 42 can be a hinged closure witha locking pall or snap feature, which also serves to ensure a single useand also as evidence of use. The hinged closure mechanism is alsopreferably liquid-tight when closed.

FIGS. 3-7 illustrate another embodiment of a cuvette assembly 110 thatis similar to the cuvette assembly 10 of FIGS. 1-2, where similarstructures are now referenced with 100-series reference numerals.Referring initially to FIGS. 3-4, the cuvette assembly 110 includes fourseparate cuvettes, each of which includes an optical chamber 112 and aliquid-input chamber 114. As with the previous embodiments, the internaland external walls of the lower portion 113 of the main body of thecuvette assembly 110 define the optical chamber 112. For example, thefirst optical chamber 112 is partially defined by the side externalwall, an internal wall, and a bottom wall of the lower portion 113, aswell as the entry and exit windows 116, 118. The associated liquid-inputchamber 114 is partially defined by a side external wall, an internalwall, and a pair of front and back external walls on the upper portion115 of the main body of the cuvette assembly 110.

Each of the four entry windows 116 is a part of an entry window assembly117 that is attached to the lower portion 113 of the main body of thecuvette assembly 110. Similarly, each of the four exit windows 118 ispart of an exit window assembly 119 that is attached to the lowerportion of the main body opposite the entry window assembly 117. Inother words, the present invention contemplates a single unitary opticalstructure that provides the transmission of the input beam into all fourrespective optical chambers 112, and a single unitary optical structurethat provides for the exit of the forward scattering signals from therespective optical chambers 112. The lower portion 113 of the main bodyincludes structural recesses that mate with the corresponding structureson the window assemblies 117, 119 for registering them in a properorientation during assembly of the cuvette assembly 110.

An intermediate partition 130 within the cuvette assembly 110 separatesthe lower portion 113 defining the four optical chambers 112 from theupper portion 115 defining the liquid-input chambers 114. Theintermediate partition 130, which is shown as being part of the lowerportion 113 (although it could be part of the upper portion 115),includes four separate groups of openings that permit the flow of liquidfrom the liquid-input chamber 114 into the associated optical chamber112. The openings can be a variety of shapes that permit the flow of theliquid. As shown, the openings progressively get longer moving from theentry window 116 to the exit window 118 because the shape of the opticalchamber 112 increases in area in the same direction. Additionally, thefilter 132 rests upon the intermediate partition 130, such that the samefilter 132 is used for each of the four regions. When the same filter132 is used for all four regions, the interior walls of the upperportion 115 must provide adequate pressure at the filter 132 to preventcrossing fluid flows through the filter 132 between adjacentliquid-input chambers 112. In a further alternative, no filter 132 ispresent because the intermediate partition 130 includes adequate sizedopenings to provide the necessary filtering of the liquid sample, orbecause the liquid samples are pre-filtered before entering eachliquid-input chamber 114.

To provide the initial introduction of the liquid samples into thecuvette assembly 110, the upper structure 138, which is attached to theupper portion 115 of the main body of the cuvette assembly 110, includesfour openings 140 corresponding to the four liquid-input chambers 114.Four sliding mechanisms 142 are located within four correspondinggrooves 144 on the upper structure 138 and are initially placed in anopened position such that the openings 140 are initially accessible tothe user for introducing the liquid samples. Each of the slidingmechanisms 142 includes a pair of projections 148 that engagecorresponding side channels at the edges of each of the correspondinggrooves 144 to permit the sliding action. Within each groove 144, thereis a latching ramp 146 over which the sliding mechanism 142 is movedwhen transitioning to its closed position. A corresponding latch 147(FIG. 4) on the underside of the sliding mechanism 142 moves over thelatching ramp 146 and creates a locking mechanism when the slidingmechanism 142 has been fully moved to the closed position. The upperstructure 138 of the cuvette assembly 110 also includes a grippinghandle 150 that permits the user to easily grasp the cuvette assembly110 during transport to and from an instrument that incorporates thelight source 20 and the sensor 22.

To help seal the cuvette assembly 110 after the liquid samples have beenplaced within the respective liquid-input chambers 114, the periphery ofthe sliding mechanism 142 adjacent to the opening 140 can be configuredto tightly mate with the walls defining the groove 144 (or undercutchannels within the groove 144) to inhibit any leakage around theopening 140 in the upper structure 138. Alternatively, a resilientplug-like structure can be located on the underside of the slidingmechanism 142 that fits within the opening 142 create a seal and inhibitleakage. Or, a gasket can be provided around the opening 140 to providea sealing effect on the underside of the sliding mechanism 142.

The upper portion 115 and the lower portion 113 of the main body of thecuvette assembly 110 can be attached to each other through varioustechniques, such as ultrasonic welding, thermal welding, with adhesive,or through interfering snap-fit connections. Similarly, the upperstructure 138 can be attached to the upper portion 115 of the main bodythrough similar techniques. And, the window assemblies 117, 119 can beattached to the lower portion 113 through the same attachmenttechniques. The width dimension of the overall cuvette assembly 110across the four cuvettes is roughly 4 cm. The length dimension of theoverall cuvette assembly 110 (i.e., parallel to the input beam) isapproximately 2 cm. The height dimension of the overall cuvette assembly110 is approximately 2 cm, such that each of the liquid input chambers114 is approximately 1 cm in height and each of the optical chambers 112is approximately 1 cm in height (although the optical chambers 112 havea varying height along the length direction due to their conical shape).In some embodiments, each optical chamber 112 is designed to containapproximately 1.2 to 1.5 cubic centimeters (i.e., approximately 1.2 to1.5 ml) of a fluid sample. Each liquid-input chamber 114 is designed tohold slightly more of the liquid sample (e.g., 1.7 to 2.5 ml), which isthen fed into the corresponding optical chamber 112.

Because each of the cuvette assemblies 110 may be used for differentapplications, the cuvette assembly 110 may use barcodes or RFID tags toidentify the type of test supported by the particular cuvette assembly110, as well as other measurement data to be taken. The instrument thatincludes the light source 20 and the sensor 110 preferably reads theRFID or barcode, and selects the software to run the appropriate opticalmeasurement tests on the cuvette assembly 110. Accordingly, the cuvetteassembly 110 preferably includes an identification label 170, which mayinclude barcodes and/or quick response codes (“QR-code”) that providethe necessary coded information for the cuvette assembly 110. Othercodes can be used as well. Specifically, when bacteria is a particlebeing checked within the liquid sample, one of the codes on the label170 may provide the protocol for the test (e.g., temperature profileover duration of test, frequency of the optical measurements, durationof test, etc.). Another one of the codes may be associated withinformation on the patient(s) from whom the liquid samples were taken,which may include some level of encryption to ensure that patient datais kept confidential. Another code may provide a quality-assurance checkof the part number or the serial number for the cuvette assembly 110 toensure that the cuvette assembly 110 is an authentic and genuine part,such that improper cuvettes are not tested. The code for thequality-assurance check may also prevent a cuvette assembly 110 frombeing tested a second time (perhaps after some type of cleaning) if itis intended for only single use.

The cuvette assembly 110 also includes a vent 180 that extends from theoptical chamber 112 into the upper portion 115 of the main body thecuvette assembly 110. The vent 180 includes a chimney-like portion thatextends upwardly from the intermediate partition 130. The chimney-likeportion is then received in a channel in the upper portion 115, whichextends to an opening 182 leading into the liquid-input chamber 114 justbelow the upper structure 138 that defines the upper boundary of theliquid-input chamber 114. Accordingly, the gas (e.g., air) that isinitially present in the optical chamber 112 can be readily displaced asthe optical chamber 112 receives the filtered liquid sample from theliquid-input chamber 114 (via the filter 132). The vent 180 can alsolead to the external environment on the outside of the cuvette assembly110.

FIG. 5 illustrates a cross-section taken along line 5-5 of the exitwindow assembly 119 in FIG. 7. The exit window assembly 119 includes thefour exit windows 118 for the four optical chambers 112. To helpminimize reflections from the input beam as it impinges on each surfaceof each exit window 118, each of the exit windows 118 is angled relativeto the central axis of the input beam by an angle “A.” The angle “A” ispreferably about 5°, but can range from about 2° degrees to about 15°.

FIG. 6 schematically illustrates the effects of the input beam withinthe optical chamber 112 of the cuvette assembly 110, as well as thegeometry of the optical chamber 112. In particular, the light source 20provides an input beam that is transmitted towards the entry window 116.The entry window 116 is tilted at an angle relative to the input beamsuch that the input beam refracts upwardly toward the intermediatepartition 130 of the cuvette assembly 110. As the input beam passesthrough the liquid sample within the optical chamber 112, a forwardscatter signal (dashed lines) is produced due to the input beamimpinging upon particles within the liquid sample. Due to variousreflections and optical scatter, the upper portion 112 a of the opticalchamber 112 becomes an irrelevant region for optical measurement. Onlythe forward scatter signal that is received by the lower portion 22 a ofthe sensor 22 is relevant to determining the characteristics (e.g.,quantity, size, and/or concentration) of the particles present withinliquid sample in the optical chamber 112. As mentioned previously, theoptical chamber 112 is conical with the angle “B” that provides forexpansion of the cross-sectional area of the optical chamber 112 in thedirection of the exit window 118. The angle “B” is in the range of about12° to 16°.

Preferably, each of the entry windows 116 and the exit windows 118 meetsthe intermediate partition 130 at acute interior angles “C” and “D”,respectively. Assuming the input beam from the light source 20 issubstantially parallel to the intermediate partition 130, the acuteinterior angles help to reduce the reflections that would otherwiseinterfere with the forward scatter signal that is received at the lowerportion 22 a of the sensor 22. For example, angle “C” may be roughly 85°such that the input beam impinges upon the entry window 116 at an angleof approximately 85° so as to refract upward slightly, while providingminimal internal reflections toward the lower portion 22 a of the sensor22. Similarly, angle “D” for the exit window 118 is roughly 89° so as toagain minimize the internal reflections that could be received at thelower portion 22 a the sensor 22, while maximizing the amount of forwardscatter signal that can be received at the lower portion 22 a the sensor22. And, as noted above relative to FIG. 5, the exit window 118 is alsoangled in the opposing place as well. In summary, the optical chamber112 and the windows 116, 118 are configured to maximize the amount offorward scatter signal that is received by the lower portion 22 a of thesensor 22, while minimizing the amount of internal reflections thatcould be received in the lower region 22 a of the sensor 22.Furthermore, it should be noted that the input beam, which has a muchhigher intensity than the forward scatter signal, can be blocked orattenuated by a beam dump after leaving the exit window 118 to reduce oreliminate the transmission of the input beam signal at the sensor 22.

Referring now to FIGS. 7-8, the cuvette assembly 110 also includesdifferent types of registration features to allow the cuvette assembly110 to be located properly on a registration platform 210 (FIG. 8)within the instrument that is used for the optical measurements. Inparticular, the cuvette assembly 110 includes a pair of sideregistration features 192 located on the lower portion 113 of thecuvette assembly 110. Further, the cuvette assembly 110 includes lowerregistration features 194 a and 194 b on a lower surface of the lowerportion 113 of the cuvette assembly 110. Finally, lower segments of thefront and back walls 196 a and 196 b extending downwardly from the lowersurface also serve as registration features for the cuvette assembly110.

With reference to FIG. 8, the side registration features 192 undergosliding engagement within corresponding vertical grooves 212 on pillarsassociated with the registration platform 210. Additionally, lowerregistration features 194 a and 194 b can slide within horizontalgrooves 214 on an upper surface of the registration platform 210. Thehorizontal grooves 214 terminate in openings that receive the lowerregistration features 194 a and 194 b (illustrated as projections) onthe cuvette assembly 110. Finally, the distance between the lowersegments of the front and back walls 196 a and 196 b corresponds to thewidth of the registration platform 210 such that cuvette assembly 110becomes nestled between adjacent pillars with the front and back walls196 a and 196 b overlying the front and back edges of the registrationplatform 210.

As can be seen best in FIGS. 4 and 6, the lower surface of the lowerportion 113 of the cuvette assembly 110, which includes the lowerregistration features 194 a and 194 b, is at angle relative to the upperstructure 138 of the cuvette assembly 110 and to the input beam from thelight source 20 due to the conical geometry of the optical chamber 112.Accordingly, the upper surface of the registration platform 210 isangled in an opposing manner that allows the input beam to be generallyhorizontal (and generally parallel to the upper structure 138 of thecuvette assembly 110) when the cuvette assembly 110 is placed on theregistration platform 210. It should be noted, however, that the cuvetteassembly 110 can be properly registered on the registration platform 210with less than these three distinct registration features illustrated inFIGS. 7-8.

Once the cuvette assembly 110 is nestled properly on the registrationplatform 210, the light source 20 can sequentially transmit the inputbeam through each of the four optical chambers 112 of the cuvetteassembly 110 and the forward scatter signal associated with theparticles within each of the liquid samples can be sequentially receivedby the sensor 22. For example, the light source 20 and sensor 22 can becontrollably indexed between positions to receive optical measurementstaken in adjacent optical chambers 112. As can be seen in FIG. 8, eachplatform 210 is capable of receiving four cuvette assemblies 110, suchthat optical measurements can be taken from sixteen different liquidsamples within the four cuvette assemblies 110 nestled on theregistration platform 210.

FIG. 9 illustrates an alternative cuvette assembly 310, which isslightly different from the embodiments previously illustrated. Inparticular, the cuvette assembly 310 includes a thin film 340 locatedover the upper structure 138 and the sliding mechanisms associated withthe openings on the upper structure 138. The thin film 340 provides anextra layer of protection to ensure no contamination enters the openingswhen the sliding mechanisms located under the film 340 are in their openpositions prior to use. Once the user has chosen to use the cuvetteassembly 310, he or she tears the thin film 340 from the upper structure138 and places the four liquid samples into each of the fourliquid-input chambers 114. Alternatively, the film 340 may have multipleperforations 342 to allow for the removal of four distinct thin filmsover the four openings.

Additionally, FIG. 9 illustrates four vacuum ports 350 that provideaccess to the four interior vacuum channels, each of which is associatedwith a respective one of the optical chambers 112. The interior vacuumchannels are similar in structure to the vents 180 in FIG. 4, exceptthey do not have the upper openings 182, thereby causing a draw of gas(e.g., air) only within the optical chambers 112. Because some types ofliquid samples may not easily pass through the filter 132, applying alower pressure to the four vacuum ports 350 serves to draw the liquidsample through the filter 132 and into the optical chamber 112. Thecuvette assembly 310 may be placed on a vacuum or suctioning platform(similar to the registration platform 210 in FIG. 8) and a correspondingset of aligned tubes or a longer manifold can overlie the vacuum ports350 to automatically apply the negative pressure, thereby resulting inthe liquid sample being pulled through the filters 132 into thecorresponding optical chambers 112. Other manual methods for applyingthe negative pressure to the vacuum ports 350 can be used as well.

FIG. 10 illustrates another alternative cuvette assembly 410 having amembrane 440 directly below the openings on the upper structure 138. Themembrane 440 could be pierced or displaced by a standard pipette,syringe tip, sharp cannula, or other tube that injects the liquid sampleinto the liquid-input chamber 114. This membrane 440 serves to protectthe integrity and/or sterility of the interior of the liquid-inputchambers 114 within the upper portion 115 of the main body, and also theoptical chamber 112 prior to use. It further provides tamper-evidence oruse-evidence for a user. The membrane 440 could also be resilient orrubber material so that it could be pierced by a sharp cannula, andstill retain the interior liquid sample within the liquid-input chamber114 after the sharp cannula is refracted. Furthermore, to the extentthat the liquid-input chamber 114 is depressurized so as to help drawthe liquid sample into the liquid-input chamber 114, the membrane 440can seal the liquid-input chamber 114 to maintain a pressure lower thanthe ambient environment (or maintain a vacuum) within the liquid-inputchamber 114.

The interior of the liquid-input chamber 114 of the cuvette assembly 410could be manufactured under a vacuum, or could contain a lyophilizedmaterial, such as an antibiotic or some other chemo-effector. Ifmanufactured under a vacuum, piercing the frangible membrane 440 with apipette or cannula would apply this vacuum to the pipette or cannulaand, thus, draw the contents into the liquid-input chamber 114.Similarly, the frangible membrane 440 and permeable filter membrane 132(FIG. 3-4) can be configured so that a vacuum in the cuvette assembly410 would draw deposited liquid samples through the permeable filtermembrane 132 for filtration of the liquid sample and/or for exposure ofthe liquid sample to a chemical coating (e.g., chemo-effector) on thepermeable filter membrane 132.

In an alternative embodiment of FIG. 10, a lower frangible membrane orseal could be incorporated below the permeable filter membrane 132. Amechanical feature can then pierce this lower frangible membrane by useraction, such as by the loading pipette or a separate tool, by flexing ofdevices in the cuvette body, or by the motion of the sliding or hingedclosure mechanisms. As an example, the lower surface of the permeablefilter membrane 132 directly adjacent to the lower frangible membranecan have a plurality of projecting features that, when forceddownwardly, cause the lower frangible membrane to be pierced. In thisalternative, the optical chamber 112 and fluid input chamber 114 areisolated until this lower frangible membrane is pierced or displaced.The lower optical chamber 112 could be in a vacuum (or other lowpressure state) compared with the liquid-input chamber 114, and piercingthis membrane could serve to apply the vacuum to the lower face of thepermeable filter membrane 132 and, thus, draw flow of the liquid samplethrough the permeable filter membrane 132.

FIG. 11 illustrates another alternative cuvette assembly 510 having amanual pump 512 on the upper structure 138 of the cuvette assembly 510.The manual pump 512 can be actuated by the user by pushing downwardly toforce a volume of air within the cuvette assembly 510 to be forced ontothe sample liquids that have been placed in the four liquid-inputchambers 114. After the sliding mechanisms 142 (FIGS. 3-4) have beenmoved to the closed position, thereby providing some sealing effectaround the openings 140, the user actuates the manual pump 512, whichcauses the sample liquids to be forced downwardly through the filter 132and into the optical chamber. Again, like the suctioning effect from thevacuum ports 350 in FIG. 9, providing a pressure differential across thefilter 132 enhances the flow of the sample liquid from the fluid inputchamber 114, through the filter 132, and into the optical chamber 112.While one common manual pump 512 is disclosed, the present inventioncontemplates a single manual pump for each of the liquid-input chambers114. Of course, an automatic pump can also apply pressure to the liquidsamples through ports in the upper portion of the cuvette assembly 510.

FIG. 12 illustrates the use of the cuvette assembly 10 in one particularapplication. While FIG. 12 illustrates the application relative to thecuvette assembly 10 of FIGS. 1-2, the application equally applies to thecuvette assemblies 110, 310, 410 and 510 illustrated in FIGS. 3-11. Infirst optical chamber 12 a, a liquid sample serves as a control for thetest. For example, the first optical chamber 12 a may be a liquid samplefrom the patient having an infection (e.g., a urinary tract infection).The second optical chamber 12 b may have the same patient's liquidsample, but mixed with a first drug (“Drug 1”) applied thereto.Similarly, the third optical chamber 12 c may have the same patient'sliquid sample, but mixed with a second drug (“Drug 2”). Likewise, thefourth optical chamber 12 d may have the same patient's liquid sample,but mixed with a third drug (“Drug 3”). Finally, the fifth opticalchamber 12 e may have the same patient's liquid sample, but mixed with afourth drug (“Drug 4”). The cuvette assembly 10 provides for asimplistic method for determining the effect of each of the four drugson the patient by measuring the bacterial content (bacteria particles)over a period of time. For example, the untreated control sample in thefirst optical chamber 12 a may result in a forward scatter signal thatincreases due to the growth of bacteria in the untreated liquid sample.But, that same liquid sample from the patient may experience less growthin the number of bacteria when exposed to Drugs 3 and 4. And, that sameliquid sample from the patient may experience no growth or a decrease inthe growth in the number of bacteria when exposed to Drugs 1 and 2.

Alternatively, Drugs 1, 2, 3, and 4 can be the same type of antibiotic,but at different levels such that the cuvette assembly is useful indetermining the “minimum inhibitive concentration” that is needed toreduce or retard bacterial growth. In short, each of the cuvetteassemblies of the present invention are useful in determining theeffects of a chemo-effector (such as an antibiotic, or a nutrient growthmedium) by allowing for an easy measurement of changes in microbialgrowth rates for liquid samples exposed to different chemo-effectors orliquid samples exposed to the same chemo-effector, but at differentconcentrations.

In one particular example, the cuvette assembly 10 has a plurality ofchambers that are loaded with different combinations of chemo-effectors(for example, pre-mixed sterile liquid growth media such as Luria Broth,each with a different concentration of some number of antibiotics). Theuser can load a small amount (e.g. 0.05 mL) of a chemo-effector sampleinto each liquid-input chamber 14 by piercing the membrane, depositingthe sample, removing the pipette or cannula. The chemo-effector sampleand liquid sample can mix, and the cuvette assembly 10 can then bemeasured and incubated in an instrument with the light source 20 and thesensor 22. The different rates of growth of a pathogen could be measuredfor each chamber that holds variable concentrations of the antibiotic,and a “minimum inhibitive concentration” can be established from theseresults in a short period. This may be incorporated into a cuvetteassembly 10 having chambers with no chemo-effectors, or chambers that donot receive liquid samples but are simply present to provide control orcalibration standards for the optical measurements associated with thelight source 20 and the sensor 22. In other words, the present inventioncontemplates an optical chamber in the cuvette assembly as containing acontrol or calibration liquid.

With regard to the specific use of a chemo-effectors, a chemo-effectormay be a dry (e.g., lyophilized) material, a coating on a surface of oneof the chambers or on the filter, a liquid or solution, a gaseousatmosphere (such as Argon, O2, or CO2), or some combination. In thepresent invention, the chemo-effector is preferably pre-loaded into thecuvette assembly 10, and closed by one of the internal membranes, films,foils, or other frangible or moveable feature for future use. Thechemo-effector may be a growth media combined with an antibiotic andcombined with other biochemical reagents. In particular, thechemo-effector could be loaded into the fluid-input chamber 14, enclosedwith a frangible membrane above it and/or below it (for example,membrane 34, filter membrane 32, 132, film 340, membrane 440, and/or afilm below the filter 132 and above the intermediate partition 130) toisolate it from the optical chamber 12. The cuvette assembly 10 wouldpermit the piercing of the frangible membranes in a sequence to providefor exposure of the chemo-effector to a loaded liquid sample, to anotherchemo effector, to a vacuum or gaseous environment, or to a permeablefilter membrane, prior to or in the process of transferring the fluidsample to the optical chamber 14.

Each of these embodiments and obvious variations thereof is contemplatedas falling within the spirit and scope of the claimed invention, whichis set forth in the following claims. Moreover, the present conceptsexpressly include any and all combinations and subcombinations of thepreceding elements and aspects.

The invention claimed is:
 1. A cuvette assembly for use in opticallymeasuring at least one characteristic of particles within a plurality ofliquid samples, comprising: a main body having a plurality of openingsand a plurality of internal walls, each opening for receiving arespective one of the plurality of liquid samples, each of the pluralityof openings leading to an associated liquid-input chamber that is influidic communication with an associated optical chamber, each opticalchamber being separated from an adjacent optical chamber by a singularone of the plurality of internal walls and having an entry window forallowing transmission of an input light beam through the respectiveliquid sample and an exit window for transmitting a forward scattersignal caused by the particles within the respective liquid sample; anda plurality of individual closure mechanisms, each of the plurality ofclosure mechanisms being associated with a respective one of theplurality of openings, each of the plurality of closure mechanisms beingmovable from an opened position for receiving the respective liquidsample to a closed position that inhibits leakage from the associatedliquid-input chamber.
 2. The cuvette assembly of claim 1, wherein eachof the plurality of individual closure mechanisms is locked in theclosed position to inhibit reopening of the closure mechanism.
 3. Thecuvette assembly of claim 1, wherein each of the plurality of closuremechanisms is slidable from the initial opened position to the closedposition.
 4. The cuvette assembly of claim 1, wherein each of theplurality of closure mechanisms is rotatable about a hinge to move fromthe initial opened position to the closed position.
 5. The cuvetteassembly of claim 1, further including a filter located between each ofthe liquid-input chambers and the associated optical chamber forfiltering the respective liquid sample received by the optical chamber.6. The cuvette assembly of claim 1, further including a vent associatedwith each optical chamber to permit the gas within the optical chamberto be displaced as the respective liquid sample enters the opticalchamber.
 7. The cuvette assembly of claim 6, wherein the vent permitsthe gas within the optical chamber to be displaced into the associatedliquid-input chamber.
 8. The cuvette assembly of claim 1, wherein themain body includes an upper portion and a lower portion, the upperportion defining the plurality of liquid-input chambers, the lowerportion defining the plurality of optical chambers.
 9. The cuvetteassembly of claim 8, further including an intermediate partition betweenthe upper portion and the lower portion, the intermediate partitionhaving a plurality of groups of openings, each of the groups beingassociated with one of the liquid-input chambers and for passing theassociated filtered liquid sample to the optical chamber.
 10. Thecuvette assembly of claim 1, further including a frangible membranewithin each of the liquid-input chambers through which a respectiveliquid sample is received by piercing the frangible membrane with apointed object.
 11. The cuvette assembly of claim 1, further including acontamination-prevention membrane located over the plurality ofindividual closure mechanisms to inhibit contamination of theliquid-input chambers via the openings when the plurality of individualclosure mechanisms are in the initial opened position.
 12. The cuvetteassembly of claim 1, further including at least one chemo-effector thatis pre-loaded into more than one of the liquid-input chambers for mixingwith the respective liquid sample, the chemo-effector in one of theliquid-input chambers being different in type or concentration from thechemo-effector in at least one other liquid-input chamber.
 13. Thecuvette assembly of claim 1, further including a window assemblyattached to the main body, the window assembly providing either all ofthe exit windows for the optical chambers or all of the entry windowsfor the optical chambers.
 14. A cuvette assembly for use in opticallymeasuring at least one characteristic of particles within a plurality ofliquid samples, comprising: a main body having an upper surface, a lowersurface, a plurality of openings along the upper surface, a plurality ofinternal walls, and a plurality of optical chambers, each opening forreceiving a respective one of the plurality of liquid samples andleading to an associated one of the plurality of optical chambers, eachoptical chamber being separated from an adjacent optical chamber by asingular one of the plurality of internal walls, and having an entrywindow for allowing transmission of an input light beam through therespective liquid sample and an exit window for transmitting a forwardscatter signal caused by the particles within the respective liquidsample; a plurality of individual closure mechanisms, each of theplurality of closure mechanisms being associated with a respective oneof the plurality of openings, each of the plurality of closuremechanisms being movable from an opened position for receiving therespective liquid sample to a closed position for inhibiting leakagefrom the cuvette assembly; and a pair of registration structuresassociated with the lower surface of the main body, the lower surface ofthe main body being angled relative to the upper surface of the mainbody, the pair of registration structures for mating with acorresponding pair of registration features on a platform in aninstrument associated with a light source producing the input lightbeam.
 15. The cuvette assembly of claim 14, wherein the pair ofregistration features includes projections extending downwardly from thelower angled surface.
 16. The cuvette assembly of claim 14, furtherincluding at least one chemo-effector that is pre-loaded into thecuvette assembly for mixing with the liquid samples.
 17. The cuvetteassembly of claim 14, wherein the lower angled surface includes aplurality of surfaces associated with the optical chambers.
 18. Thecuvette assembly of claim 14, wherein the main body includes an upperportion and a lower portion, the upper portion defining a plurality ofliquid-input chambers, the lower portion defining the plurality ofoptical chambers.
 19. The cuvette assembly of claim 14, furtherincluding a second pair of registration structures associated with theangled lower surface, the second pair of registration structures formating with a corresponding second pair of registration features on theplatform in the instrument associated with the light source producingthe input light beam.
 20. The cuvette assembly of claim 19, wherein thesecond pair of registration features including lower wall segments ofthe main body extending downwardly for engaging regions of the platform.